Experimental design: D(-7): animal distribution into feeding regime groups. D(0): start of a weekly trickle infection of H, contortus and T. colubriformis for 6 weeks D(7), D(14), D(21), D(28), D(35) and D(42). D(63): slaughter and necropsy of 8 male lambs par group. Measurements of BW: body weight were performed on D0 and D63, FECs: faecal egg counts (weekly) and B: blood sampling to measure PCV (fortnightly).